The present invention relates to an elastic interconnector, referred to simply as a connector hereinafter, or, more particularly, to a connector used for making electrical connection between two arrays of electrode terminals on two oppositely facing electronic devices such as printed circuit boards and the like irrespective of the types of the electronic circuits involved Which may be an analogue circuit or a digital circuit.
Connectors of one of the most widely used types are those formed by alternately stratifying each a plural number of layers of an electrically insulating rubbery material and layers of an electrically conductive rubbery material. A most conventional rubbery material for these insulating and conductive rubbery layers is a silicone rubber by virtue of the excellent electrical properties including good insulation while an electroconductive silicone rubber is obtained by compounding a silicone rubber with a large amount of fine particles of a conductive material such as carbon and metals. One of the problems in such a silicone rubber-based electroconductive rubbery material is that the volume resistivity of such a conductive rubbery material cannot rarely be low enough and it is a rather difficult matter that the electrically conductive rubbery layer formed from a silicone rubber-based conductive rubbery material has an electric resistance lower than 1 k .OMEGA. with good reproducibility. Therefore, silicone rubber-based connectors of the above mentioned type are not always suitable for the connection of analogue or digital electronic circuits in which a considerably large electric current passes through the conductive layers of the connector and high accuracy is required for the resistance thereof if not to mention the relatively high costs of such connectors.
When carbon black is used as the conductivity-imparting particulate material dispersed in the matrix of a silicone rubber to prepare a conductive silicone rubber, in particular, the volume resistivity of the conductive silicone rubber material usually exceeds 0.2 .OMEGA..cm so that connectors prepared by using such a conductive silicone rubber cannot be used for the connection of analogue circuits and high-frequency digital circuits. Another problem in carbon black-loaded conductive silicone rubber materials is that, when the volume resistivity of the rubber is desired not to exceed 0.4 .OMEGA..cm, the-loading amount of carbon black must be so high that the carbon black-loaded silicone rubber has an increased hardness and is poor in the rubbery elasticity to exhibit a higher than adequate compressive stress under compression when the connector is in service and hence the rubbery connector made from such a high-hardness rubber is not suitable for use under compression in order to ensure reliability of the electric contacting between the electrode terminals and the conductive rubber layers of the connector. Further, the electric current passing through a conductive silicone rubber layer cannot be larger than 1 mA because of the temperature elevation sometimes to exceed 50.degree. C. due to the high resistivity of the conductive layer. This problem due to the high compressive stress cannot be solved by using a metallic powder as the conductivity-imparting agent. In addition, the reliability of electric conduction through such an electroconductive rubber is relatively low under repeated use by compression because the electric conduction therethrough is obtained by the direct contacting between the metallic particles dispersed in the rubbery matrix.